JP2021510635A - Methods for making molds and cores suitable for making fiber composites or cast parts of metals or plastics, mold base materials and binders used in this method, and molds and cores made by this method. - Google Patents

Abstract

The present invention relates to a method for producing a suitable mold and core for producing a fiber composite or a metal or plastic cast part from a granular mold base material and a multi-component binder by 3D printing. According to the present invention, the granular mold base material is pretreated with at least one silicon-organic compound having polar hydrophilic and non-polar hydrophobic ends. After the layer of pretreated granular mold base material is formed, the binder or at least one component of the binder is applied to the layer in liquid form. Silicon-organic compounds are included in the molds and wicks produced according to the present invention. The mold base material and the silicon-organic compound can be part of a set used to carry out the methods of the invention. [Selection diagram] None

Description

The invention described below is a method for producing a mold and a core suitable for producing a fiber composite or a metal or plastic cast part from a granular mold base material and a multi-component binder by 3D printing. With respect to mold base materials and binders that can be used in this method, and molds and wicks produced by this method.

There are numerous industrial products that use components made of metal, plastic, or fibrous composites (composites containing a matrix of plastics embedded in the fibrous material) that have cavities inside. Manufacture of such components, especially if the cavity has a complex geometry (eg, a shape with elongated curved shapes or notches), while the cavity surface must also have a high grade of smoothness. Have difficulty. One possible way to make such components in one piece is to cast them using what is called "lost molds". In this technique, in the upstream process, a mold part (“core”) is produced, which corresponds to the cavity formed in size and shape. The wick is placed in the casting tool. The casting tool comprises an additional mold portion into which a liquid metal, a liquid polymer material, or a liquid polymer precursor is continuously injected. In the production of fibrous complexes, the core is wrapped in fibrous material before being placed in the casting tool. After casting, a fiber complex or metal or plastic cast part with the desired cavity is obtained, in which the core is still present. This wick is subsequently removed, but the removal operation is not possible without destroying the wick due to the above-mentioned complex geometry of the cavity. The core as a mold part is "disappeared".

For example, using a core of an inorganic material such as sand to form a cavity in a cast part is a known technique from metal casting. This type of wick can also be used for casting plastics as the surface of the wick is sealed. They are made from a molding mixture containing a binder and a suitable granular inorganic material called a mold base material. The binder holds the particles of the mold base material together and thus is responsible for the structural integrity of the wick. The wick must be able to withstand the thermal and mechanical loads generated during the casting procedure. After casting, the wick is usually crushed by vibration. If water-soluble binders are used (eg, magnesium sulfate, waterglass, polyphosphate and / or borate-based binders are used), the core should be flushed from the inside of the cast part after the casting procedure. Can be done.

In order to produce such a core from an inorganic material, a molding mixture containing a heat resistant mold base material (usually sand) and a binder is usually produced. This mixture is processed into a desired mold or desired core in a molding tool. In order to manufacture a wick, in the so-called wick injection process, the molding mixture is a wick box (generally a molding tool consisting of two mold parts or halves at a specified pressure and a specified temperature. In use, it is introduced into at least one internal cavity (enclosing a "mold cavity") in the shape of the core being manufactured. After the binder has hardened, the finished wick is removed from the wick and used as intended.

Nowadays, molds and wicks are often manufactured by 3D printing. A printer for producing a 3D component usually has at least one movable print head, which operates in the same manner as a print head of a conventional inkjet printer. However, instead of ink, the printhead typically applies a liquid binder to a layer of heat-resistant mold-based material. In this case, it can be the separate 2D layers of the 3D model that act as the basis for the data, and the 3D model is decomposed into these same separate 2D layers by the computer.

In order to form the mold or core for cast plastic or metal layer by layer by 3D printing, a first layer of heat resistant mold base material is placed in the frame. The binder is then applied via at least one print head in the first printing step. The binder binds the individual particles of the mold base material to each other. Expressed in simplified terms, a 3D printer draws a two-dimensional image of the first layer of 3D components. A second layer of heat resistant mold base material is then formed on top of the first layer. In the second printing step, the binder is similarly applied to this layer. The amount of binder is calculated to not only bind the particles of the mold base material in the second layer to each other, but also to bind the particles in the first layer to the particles in the second layer. Layer by layer, the 3D component is constructed in this way. Of particular note here is the need for uniform application of the individual layers. Generally, the layer must be compressed prior to application of the binder. This is done, for example, by rollers or vibrations.

Suitable devices for making molds and wicks by 3D printing are commercially available. Suitable 3D printer structures for making molds and wicks are schematically shown in FIG. 1 of WO2016 / 019937A1 of Voxeljet AG, for example.

DE102014118577A1 discloses a method for manufacturing molds and cores by 3D printing. In this method, the binder used is a mixture of water glass and at least one phosphate and / or at least one borate, and the mold base material used also includes materials such as silica sand. A hardener for the binder may be added to the mold base material.

WO2012 / 175072A1 discloses another method for manufacturing molds and wicks by 3D printing. In this method, a layer of heat-resistant mold-based material is formed to build the 3D component layer by layer, to which a spray-dried solution of alkali metal silicate is added. This solution can be activated using water, which is applied to the layer via the printhead, which allows the particles of the mold base material moistened with water, after the subsequent drying step. , Combine with each other.

WO2011 / 087564A1 also discloses a method for manufacturing molds and cores by 3D printing. In this method, a printable mixture is formed from a heat resistant mold base material, cement, and water glass and is used to build the 3D component layer by layer.

A possible problem with 3D printing of molds and cores is that when applying a water-based binder, the binder does not stay in its directly applied position and sinks into the lower layer due to gravity. Is. In addition, the binder may flow laterally, binding the individual particles of the mold base material to each other outside the area to be printed. This effect is also known by the term "fluid transition". This problem arises as each layer is further printed, as the time between printing of successive layers is often too short for the already printed layers to dry and / or cure to a sufficient degree. Tends to get worse. Depending on the adsorption capacity of the mold base material, this can result in a very significant deviation from certain geometrical specifications regarding the mold or core to be printed.

There are a number of factors (generally more than one) that can affect the degree of fluid migration. These are, in particular, the amount and concentration of binder and the energy input in curing the added binder. A detailed description of this agenda, for example Ramakrishnan, Robert of "3D-Drucken mit einem anorganischen Formstoffsystem" [3D Printing with an inorganic molding material system] from 2016 (submitted on 24 September, 2015 at the Technical University Munich, and assisted by the Facility of Machinery on January 25, 2016; Present UNiv.-Prof. Dr.-Ing. Gunther Reinhart, Examiners-Univ.-Prof. .Nat.Tim C.Lueth) found in the dissertation.

It is an object of the present invention to provide an improved method in these respects for providing molds and cores for producing fiber complexes or cast metal or plastic parts by 3D printing.

In order to achieve this object, the present invention relates to a method having the characteristics specified in claim 1, a mold and a core having the characteristics specified in claim 11, and a granular base having the characteristics specified in claim 12. A material and a set having the characteristics specified in claim 13 are proposed.

The methods according to the invention are as useful as the methods known in the art and discussed at the outset for producing molds and cores suitable for producing fiber composites or cast parts of metals or plastics. .. According to the present invention, the mold and core are manufactured by 3D printing from a granular mold base material and a multi-component binder. The method of the present invention always includes the following steps.
(A) A step of pretreating a granular mold base material with at least one silicon-organic compound having polar hydrophilic and non-polar hydrophobic ends.
(B) The step of forming a layer of pretreated granular mold base material, and (c) the binder or at least one component of the binder (in short, the binder component) in liquid form (usually in a 3D printer). The process of applying to a layer (via one or more printheads).

In this case, steps (b) and (c) are repeated a plurality of times, as in the conventional procedure described at the beginning for manufacturing the mold and core by 3D printing. The binder or at least one component thereof is applied to the first layer of the pretreated mold base material, followed by the formation of a second layer of the pretreated mold base material on top of the first layer. , Subsequent to the binder or at least one component thereof. This is repeated until the construction of the desired mold or core layer by layer is complete.

Mold-based material The mold-based material preferably comprises a granular material in which the hydrophilic end of the silicon-organic compound can be attached to the surface of the granular material. The mold base material used preferably comprises such a material. The pretreated mold base material preferably comprises a granular material and a silicon-organic compound.

In a preferred embodiment, the granular material comprises at least one granular inorganic material that is insoluble in water (at room temperature). This material is preferably selected from the group having sand, glass, oxides, ceramics, metals, glass-ceramic materials, and mixtures of said materials.

The sand can be of natural or synthetic origin. Particularly envisioned are silica sand, zircon sand, chrome ore sand, mullite sand, and olivine sand.

Suitable glasses are inorganic glasses that are chemically inert to water or aqueous solutions, especially in the temperature range of at least 0 ° C to 200 ° C.

Among the known oxide materials, particularly suitable ones are metal oxides such as aluminum oxide.

Ceramic particles also refer specifically to carbides, nitrides, oxides, silicide particles, and known clay minerals such as kaolinite.

The term "glass-ceramic" refers to glass in which crystalline ceramic particles are embedded in an amorphous glass phase.

Granular materials, additionally or alternatively, are hollow microbeads (particularly hollow aluminum silicate microbeads and / or hollow glass microbeads), granules, and / or spheres based on glass, ceramics, metals or metal alloys. Can be.

It is also possible to use recycled glassware (eg, glass granules and expanded glass granules), expanded clay, and other inexpensive particulate matter.

The use of low melting point particles (eg, low melting point glass particles) is usually only suitable for making molds used for making fiber composites or cast parts of plastics. For the processing of liquid metals (eg, liquid aluminum), the molds of these materials are less suitable. Particularly suitable mold base materials in this case are sand having high temperature resistance and the above-mentioned ceramic particles.

The granular material has a melting point of preferably higher than 600 ° C, more preferably higher than 900 ° C, still more preferably higher than 1200 ° C, and particularly preferably higher than 1500 ° C.

In a number of more preferred embodiments, the selected mold base material comprises at least one granular inorganic material that is soluble in water (at room temperature). This is preferably a water soluble salt.

Water-soluble salts that can be used include salts from the group of sodium chloride (NaCl), potassium chloride (KCl), and sodium carbonate (Na ₂ CO _{3) in particular.} It also contains nitrates, especially sodium nitrate (NaNO ₃ ) and potassium nitrate (KNO _3).

The salts described above are particularly suitable for molds used for the manufacture of fibrous composites or cast parts of plastics.

In a number of more preferred embodiments, the selected mold base material comprises at least one granular organic material that is soluble in water (at room temperature). It is preferably a water-soluble polymer or salt of an organic acid (eg, sodium acetate), or a mixture of these materials, or urea, citric acid, or tartaric acid.

These materials are particularly suitable for molds used for the production of cast parts of fiber composites or low melting point plastics.

The granular mold base material preferably has an average particle diameter (d50) of 10 μm to 800 μm, more preferably 30 μm to 300 μm.

Additionally, the mold base material of the particulate preferably ^has a surface area determined in accordance with ^{50cm 2 / g~500cm 2 / g DIN} -ISO 9277 in the range of.

The particle size distribution of the mold base material is preferably selected so that the cores and molds produced provide a densely packed structure that corresponds to the experimentally determined Fuller or Litzow particle size distribution. It is preferably used to minimize the permeated pore space.

Silicon-Organic Compounds The polar hydrophilic ends of silicon-organic compounds are hydroxyl (-OH), hydroxylate (-O-), amino (-NH ₂ ), ammonium (-NH ₄ ⁺ ), carboxyl (-COOH), Alternatively, it preferably contains at least one functional group selected from the group consisting of carboxylate groups. In particular, the hydrophilic end can also contain two or more of these groups (eg, two or more hydroxylate groups).

Non-polar hydrophobic ends of silicon-organic compounds include those from the group consisting of at least one alkyl group, preferably methyl, ethyl and propyl. In a preferred embodiment, the hydrophobic end can also include two or more alkyl groups.

In one preferred embodiment, the polar hydrophilic and non-polar hydrophobic ends are attached to the same Si atom. In this case, the silicon-organic compound used preferably comprises an alkyl silanolate, particularly an alkali metal methyl silanolate, more preferably a potassium methyl silanolate.

In a further preferred embodiment, the silicon - organic compound, tripotassium methyl silane trioleate (empirical formula is CH 3 _K 3 _O 3 _Si, also known as potassium methyl siliconate) is.

In a further particularly preferred embodiment, the non-polar hydrophobic end of the silicon-organic compound is attached to the Si atom and the polar hydrophilic end of the silicon-organic compound is attached to the C atom. In this case, Si atoms and C atoms are connected via a chain having n atoms, n is an integer of 1 to 150, and n atoms are from C atom, O atom, and Si atom. It is more preferable to be selected from the group.

式中、ｎは、１〜１００の整数であり、ｍは、１〜１０の整数であり、Ｒは、Ｈ原子である。 In a more preferred embodiment, the silicon-organic compound comprises a compound having the following structural formula (I):

In the formula, n is an integer of 1 to 100, m is an integer of 1 to 10, and R is an H atom.

In a particularly preferred embodiment, the silicon-organic compound comprises 3- (polyoxyethylene) propylheptamethyltrisiloxane.

Pre-treated mold-based material For pre-treatment, the granular mold-based material is added with at least one silicon-organic compound. In this case, there is an optimum value for the amount of the silicon-organic compound added to the mold base material. If this ratio is too low, the addition of silicon-organic compounds may not be sufficiently effective. If this ratio is too high, the granular mold base material may become too hydrophobic and the individual particles of the mold base material may no longer fully interact with the binder during subsequent printing operations.

The pretreated mold base material is usually in the form of a free-flowing product.

More preferably, the silicon-organosilicon is at least 0.001% by weight and at most 0.1% by weight in the pretreated mold base material (based on the dry weight of the pretreated mold base material). Silicon-organosilicon is added to the granular mold base material during pretreatment in an amount that is present in proportion. Within this range, a ratio of 0.01% by weight to 0.05% by weight is more preferable. This is especially true if the granular mold base material used has an average particle diameter (d50) of 10 μm to 800 μm, and the silicon-organic compound used is alkali metal methyl silanolate, more preferably potassium methyl silicate. This is true if it contains or is a compound of structural formula (I), in particular a 3- (polyoxyethylene) propylheptamethyltrisiloxane.

The amount of silicon-organic compound added to the granular mold base material also affects the extent to which the "fluid migration" described above occurs. It can be confirmed by experimental studies that the optimum value of the weight ratio of the silicon-organic compound is particularly 0.01% by weight to 0.1% by weight.

Suitable procedures for this purpose are known from the Ramaklishnan dissertation described above. It involves producing a standardized test sample containing a structure consisting of multiple concentric rings according to specific printing parameters. After these test samples have been produced, they are blown off with compressed air at a specified working pressure of 8 bar. The air stream removes the unbonded granular material in the interstices of the ring. After these materials have been blown off, the weight of the test sample is checked by a precision balance.

The greater the degree of fluid transfer, the more material remains in the gap in the form of an adhesive. These adhesives increase the weight measured by a precision balance.

"Fluid transfer" represents a percentage of the weight of a test sample that exceeds its intended weight. It can be calculated from the density of the disc-shaped test sample and the nominal volume of the test element (obtained from CAD data). By using silicon-organic compounds, it is possible to produce test samples whose weight deviates less than 0.1% of their intended weight.

The silicon-organic compound is preferably attached to the surface of the pretreated mold base material, particularly via its hydrophilic end.

Binder In a preferred embodiment, the binder has the following characteristics:
-It contains at least one water-soluble binder component.
-It contains at least one water-insoluble binder component.
-It contains water or aqueous solutions, especially alkaline aqueous solutions.

The binder is optionally at least one additive that affects its processing properties (eg, wetting agents such as polyethylene glycol, sodium 2-ethylhexyl sulfate (Sulfetal), surfactants (Byk) or fluid additives. )including.

The water-soluble binder component preferably comprises at least one material from the group consisting of water glass, magnesium sulfate, phosphate, and borate.

Waterglass is a term that refers to both glassy water-soluble alkali metal silicates (particularly sodium silicate, potassium and lithium) solidified from the melt and their aqueous solutions. Sodium waterglass is particularly suitable for use in the context of the present invention. It is also possible to use a mixture of two or more different water glasses.

One characteristic of water glass is their coefficient (modulus), the term _{meaning the molar ratio of SiO 2} : M ₂ O in water glass, where M is Li ⁺ , K ⁺ or It is preferably selected from Na ^+. Water glass preferably has a coefficient of 1.2 to 4.5, more preferably 1.5 to 3.3.

GB782205A discloses an alkali metal water glass which is a suitable binder for use in the context of the present invention and which _{can be cured by the introduction of CO 2.} Further suitable waterglass-based binders are known, for example, from DE19921567A1, DE102007045649A1 or US5474606A.

Borate is a salt or ester of boric acid. Boric acid can itself be included in borate and is often referred to as trihydrogen borate. The salts are characterized in that their ion lattice contains borate ions BO ₃ ^3- and / or condensed forms thereof (eg, B ₄ O ₅ (OH) ₄ ^{2- 2} , tetraborate) as anions.

As the phosphate, not only conventional phosphate (for example, ammonium phosphate) but also hydrogen phosphate such as polyphosphate and sodium hydrogen phosphate can be used.

Polyphosphate is known as a condensate of a salt of orthophosphoric acid (H ₃ PO ₄ ), and has a general empirical formula M _{n + 2} P _n O _{3 n + 1} and a structure MO- [P (OM) (O) -O] _n. It has −M, where M is a monovalent metal and n can be a number up to 3 or 4. However, polyphosphates often also include short chain (ie, oligo) phosphates, where n can be a number from 8 to 32. Cyclic polymers are referred to as metaphosphates.

Binders suitable for use in the context of the present invention, based on polyphosphate and / or borate, are disclosed, for example, in WO 92/06808A1. Further suitable phosphate-based binders are known, for example, from DE10359547B3, DE19525307A1 or US5711792A.

In a particularly preferred embodiment, the phosphate in the binder used in the present invention comprises sodium hexametaphosphate ((NaPO ₃ ) ₆ ).

The water-insoluble binder component preferably comprises at least one material from the group consisting of granular silicon dioxide (particularly granular amorphous silicon dioxide) and granular calcium carbonate.

It may be advantageous to add silicon dioxide to the molding mixture along with a water glass based binder from E. coli. I. du Pont de Nemours and Co. It is already known from DE2434431A1 of. As a result of such addition, a significant increase in the strength of the water glass bonded mold and core can be achieved.

Granular silicon dioxide is preferably used as a suspension in water, particularly preferably as a colloidal aqueous suspension. The suspension used in this case preferably has a solid content in the range of 10% to 80% by weight (based on the total weight of the suspension used).

In a particularly preferred embodiment, the suspension is preferably a suspension of particles produced by condensation of low molecular weight silica. Alternatively, granular silicon dioxide can be produced in another way, for example by flame thermal decomposition from silicon tetrachloride. Natural amorphous silica can also be used, an example of which is disclosed in DE102007045649A1.

Granular silicon dioxide preferably has an average particle diameter (d50) in the range of 5 nm to 1.5 μm, more preferably 10 nm to 1 μm.

The production of granular colloidal suspensions by condensing low molecular weight silica is a known procedure. Low molecular weight silicas (eg, monosilica (orthosilica), disilica, or trisilica) are prone to condensation, especially under acidic or basic conditions. Condensation of these low molecular weight silicas forms the desired colloidal suspension. These suspensions are commercially available in a very wide variety of average particle sizes.

The particles and colloidal suspensions particularly preferably used in the present invention are preferably prepared starting from pure monosilica.

The binder used in the present invention is more preferably formed by combining the following components in the following proportions.
At least one water-soluble binder component in a proportion of 40% to 99% by weight, more preferably 50% to 80% by weight.
At least one water-insoluble binder component in a proportion of 1% to 40% by weight, more preferably 5% to 30% by weight.
Water or aqueous solution in the range of 10% to 60% by weight, especially an alkaline aqueous solution.

All percentages are based on the total weight of all components of the binder, including water or aqueous solution. The proportion of the components is 100% by weight in total.

Modifications of the Applying Method In principle, it is possible to give the binder in the form of a mixture of all its components and apply this mixture to a layer of pretreated granular mold base material. However, in one particularly preferred embodiment, at least one component of the binder is present as a stationary binder component in the layer of mold base material and only the remaining components of the binder are in liquid form. Granted to the layer.

In a modification of the first preferred method, the fixed binder component comprises a water-insoluble binder component, or one of a plurality of water-insoluble binder components. Particularly preferably, the mold base material in this case is pretreated with a fixed binder component. Thus, for example, the mold base material is mixed with the suspension of colloidal aqueous silicon dioxide described above prior to forming a layer of the mold base material, wherein the remaining components of the binder (eg, water glass) are liquid. In the form, it can be applied particularly via the printheads (s) described above.

At least one binder component imparted to the layer in liquid form is water, an aqueous hydroxide solution (particularly an aqueous solution of sodium hydroxide or potassium hydroxide), a water glass solution, depending on the particular binder used. It preferably contains at least one material from the group consisting of an aqueous solution of magnesium sulfate, an aqueous solution of phosphate, and an aqueous solution of borate.

In a modification of the second preferred method, the fixed binder component comprises one of a water-soluble binder component, or a plurality of water-soluble binder components. Again, particularly preferably, the mold base material is pretreated with a fixed binder component. Thus, for example, the mold base material is mixed with water glass prior to forming a layer of the mold base material, in which the remaining components of the binder (eg, the suspension of colloidal aqueous silicon dioxide described above) are liquid. It can be given in the form.

Modifications of Thermosetting and Self-Curing Methods Depending on the binder used, it may be preferable that the binder be cured after the addition of the binder to the layer or the addition of at least one component of the binder. .. For this, the following steps are available as options:
-Curing is caused by microwave radiation.
-Curing occurs chemically, especially by CO ₂ or by self-curing additives.
-Curing occurs thermally.

Modifications of this type of thermosetting method can be advantageous, for example, under the following conditions.
-The mold base material is sand treated with alkyl silanolate, especially potassium methyl silicate.
-A water glass solution is added as a liquid binder component to the layer.

In this case, it is preferable that the curing is caused by microwave radiation. It may be preferable that the silicon dioxide described above be present as a fixed binder component in the layer of the mold base material, especially when producing wicks or molds for casting applications.

However, in most preferred embodiments of the methods of the invention, the binder is selected to be self-curing. Modifications of two particularly preferred self-curing methods are described below.

In the case of one modification (1) using a self-curing binder:
-The mold base material is sand treated with a silicon-organic compound according to structural formula (I).
-Ester hardeners (eg, diacetin or triacetin) are present as hardeners as fixed binder components in the layers of the mold base material.
-A water glass solution is added as a liquid binder component to the layer.

In a variant of this method, microwave curing is no longer necessary, instead curing is achieved by sol-gel conversion with a curing agent without the use of thermal energy. Again, when making wicks or molds for casting applications, it may be preferable that the granular silicon dioxide described above be present as a fixed binder component in the layer of mold base material.

In the case of another modification (2) using a self-curing binder:
-The mold base material is sand treated with a silicon-organic compound according to structural formula (I).
-Waterglass is present as a fixing component of the binder in the layer of mold base material.
An ester hardener (eg, diacetin or triacetin) is added as a liquid binder component to the layer.

In a variant of this method, microwave curing is no longer necessary, instead curing is achieved by sol-gel conversion with a curing agent without the use of thermal energy. Again, when making wicks or molds for casting applications, it may be preferable that the granular silicon dioxide described above be present as a fixed binder component in the layer of mold base material.

Molds and Cores Produced by the Method The molds and cores produced by the method have a ratio of silicon-organic compounds in the range of 0.01 to 0.09% by weight.

In a preferred embodiment, it has one of the following features or a combination of the following features:
At least one from the group consisting of magnesium sulphate, phosphate, and borate, with molds and wicks particularly in the proportion of 0.3-2.5% by weight, more preferably 0.5-1.0% by weight. Including material.
The mold and core contain granular silicon dioxide having an average particle diameter (d50) in the range of 5 nm to 1.5 μm, especially in the proportion of 0.1 to 1.0% by weight.

Set for manufacturing molds and wicks The set of the present invention always contains the following components:
-At least one silicon-organic compound having polar hydrophilic and non-polar hydrophobic ends, and-at least one material from the group consisting of water glass, magnesium sulphate, phosphate, and borate.

These two components are generally present separately from each other in the set.

In a preferred embodiment, the set further comprises at least one of the following components:
・ Granular mold base material,
-At least one material from the group consisting of silicon dioxide and calcium carbonate, and / or-Aqueous hydroxide solution.

In certain preferred embodiments, of these additional components, the solid component is already mixed with the granular base material.

Further features of the invention, and the advantages that result from it, are evident from the examples below. The embodiments described below serve only for illustration purposes and for a better understanding of the invention and should not be construed as any limitation.

(1) Provision of Granular Mold Base Material Pretreated with Potassium Methyl Siriconate Freihung, 99.98 parts by weight of type GS14 sand from STROBEL QUARZSAND GmbH in Germany (average particle size: 0.13 mm; theoretical ratio) To the surface area: 176 cm ² / g), 0.02 parts by weight of an aqueous solution having a potassium methyl silicate ratio of 34% by weight was added and completely mixed.

(2) Provision of Granular Mold Base Material Pretreated with 3- (Polyoxyethylene) propylheptamethyltrisiloxane Freihung, 99.98 parts by weight of sand of type GS14 from STROBEL QUARZSAND GmbH in Germany (average particle size: 0.02 parts by weight of 3- (polyoxyethylene) propylheptamethyltrisiloxane was added to 0.13 mm; theoretical specific surface area: 176 cm ^{2 / g) and mixed thoroughly.}

(3) Provision of Printable Water Glass-Containing Binder Component As a water glass-containing binder component, Betol 50T (modified aqueous solution of sodium silicate, coefficient: 2.6; solid content ratio: 44% by weight (Woolner) GmbH & Co. KG, Ludwigshafen, Germany)) was mixed with water and optionally a small amount of surfactant.

(4) Provision of Water-Insoluble Binder Component As the first water-insoluble binder component, amorphous SiO ₂ powder of synthetic origin (average particle size 0.1 to 0.3 μm) was provided.

(5) Manufacture of Core Using Self-Curing Binder 99 parts by weight of the mold base material pretreated in (2) for manufacturing a core for aluminum casting was provided in SiO _{2 in (4).} It was mixed with 1 part by weight of the powder. A layer was formed from this mixture. This layer was subsequently compressed. The formed layer had a uniform layer thickness in the range of 0.2 mm to 0.5 mm. The water glass-containing binder component provided in (3) was applied to the area above this layer by printing. After printing was performed, a new layer of mixture was formed on top of the printed layer and compressed to a layer thickness in the above range. This layer was again printed with the water glass-containing binder component provided in (3). This procedure was repeated until the desired core was completed. The core was cured by microwave radiation.

The cured wicks satisfied much better geometry specifications than wicks manufactured under comparative conditions using untreated mold base material.

Claims (13)

A method for producing a suitable mold and core for producing a fiber composite or a metal or plastic cast part from a granular mold base material and a multi-component binder by 3D printing.
(A) A step of pretreating a granular mold base material with at least one silicon-organic compound having polar hydrophilic and non-polar hydrophobic ends.
(B) the step of forming a layer of pretreated granular mold base material, and (c) the step of applying the binder or at least one component of the binder to the layer in liquid form.
Including
A method in which steps (b) and (c) are repeated a plurality of times. The method of claim 1, which has at least one of the following additional features and / or additional steps:
(A) The mold base material comprises a granular material, and the hydrophilic end of the silicon-organic compound can be bonded to the surface of the granular material.
(B) The selected mold base material comprises at least one water-insoluble inorganic material.
(C) At least one water-insoluble inorganic material is selected from the group comprising sand, glass, oxides, ceramics, glass-ceramic materials, and mixtures of said materials.
(D) The selected mold base material comprises at least one water-soluble inorganic material.
(E) At least one kind of water-soluble inorganic material is a water-soluble salt.
(F) The selected mold base material comprises at least one water-soluble organic material.
(G) At least one water-soluble organic material is a water-soluble polymer or salt of an organic acid, or a mixture of these materials.
(H) The granular mold base material has an average particle diameter (d50) of 10 μm to 800 μm, preferably 30 μm to 300 μm.
(I) granular type base material ^has a surface area determined in accordance with ^{50cm 2 / g~500cm 2 / g DIN} -ISO 9277 in the range of. The method of claim 1 or 2, which has at least one of the following additional features and / or additional steps:
(A) The polar hydrophilic end of the silicon-organic compound is hydroxyl (-OH), hydroxylate (-O-), amino (-NH ₂ ), ammonium (-NH ₄ ⁺ ), carboxyl (-COOH), or Contains carboxylate groups,
(B) Non-polar hydrophobic ends of silicon-organic compounds include those from the group consisting of at least one alkyl group, preferably methyl, ethyl and propyl.
(C) Polar hydrophilic and non-polar hydrophobic ends are attached to the same Si atom.
(D) The silicon-organic compound used comprises an alkyl silanolate, particularly an alkali metal methyl silanolate.
(E) The non-polar hydrophobic end of the silicon-organic compound is bonded to the Si atom, and the polar hydrophilic end of the silicon-organic compound is bonded to the C atom.
(F) Si atoms and C atoms are connected via a chain having n atoms, n is an integer of 1 to 150, and n atoms are derived from C atom, O atom, and Si atom. Selected from the group of
(G) The silicon-organic compound used comprises a compound having the following structural formula (I).

In the formula, n is an integer of 1 to 100, m is an integer of 1 to 10, and R is an H atom.
(H) The silicon-organic compound used comprises 3- (polyoxyethylene) propylheptamethyltrisiloxane. The method of any of claims 1-3, comprising the following additional steps:
(A) For pretreatment, the silicon-organic compound is at least 0.01% by weight and at most 0% in the pretreated mold base material (based on the dry weight of the pretreated mold base material). The step of adding the silicon-organosilicon to the granular mold base material during pretreatment in an amount such that it is present in a weight ratio of 2% by weight. The method according to any one of claims 1 to 4, having at least one of the following additional features and / or additional steps:
(A) The binder comprises at least one water-soluble binder component.
(B) The water-soluble binder component comprises at least one material from the group consisting of water glass, magnesium sulfate, phosphate, and borate.
(C) The binder comprises at least one water-insoluble binder component.
(D) The water-insoluble binder component comprises at least one material from the group consisting of granular silicon dioxide and calcium carbonate.
(E) The binder comprises water or an aqueous solution, particularly an alkaline aqueous solution.
(F) The binder comprises an additive that affects its processing properties. The method of any of claims 1-5, which has at least one of the following additional features and / or additional steps:
(A) At least one binder component is present as a fixed binder component in the layer of the mold base material.
(B) The fixed binder component is one of a water-insoluble binder component or a plurality of water-insoluble binder components.
(C) The fixed binder component is one of a water-soluble binder component or a plurality of water-soluble binder components.
(D) The mold base material has been pretreated with a fixed binder component.
At least one of the group consisting of water, an aqueous oxide solution, a water glass solution, an aqueous solution of magnesium sulfate, an aqueous solution of phosphate, and an aqueous solution of borate, at least one binder component imparted to the layer (e) in a liquid form. Material. The method of any of claims 1-6, which has at least one of the following additional features and / or additional steps:
(A) After the addition of the binder to the layer or the addition of at least one component of the binder, the binder is cured.
(B) Curing is caused by microwave radiation,
(C) Curing occurs chemically,
(D) Curing occurs thermally. The method of claim 6 or 7, which has the following additional features and / or additional steps:
(A) The type base material is sand treated with alkyl silanolate, especially potassium methyl silicate.
(B) Optionally, silicon dioxide (for mold use) is present as a fixed binder component in the layer of the mold base material.
(C) The water glass solution is imparted as a liquid binder component to the layer.
(D) Curing is caused by microwave radiation. The method of claim 6 or 7, which has the following additional features and / or additional steps:
(A) The type base material is sand treated with a silicon-organic compound according to structural formula (I).
(B) Optionally, silicon dioxide is present as a fixed binder component in the layer of the mold base material.
(C) The ester curing agent is present as a curing agent as a fixed binder component in the layer of the mold base material.
(D) A water glass solution is applied as a liquid binder component to the layer. The method of claim 6 or 7, which has the following additional features and / or additional steps:
(A) The type base material is sand treated with a silicon-organic compound according to structural formula (I).
(B) Optionally, silicon dioxide is present as a fixed binder component in the layer of the mold base material.
(C) Water glass is present as a fixing component of the binder in the layer.
(D) An ester curing agent is added as a liquid binder component to the layer. A mold and core suitable for producing fiber complexes or cast metal or plastic parts.
(A) The mold and core have a ratio of silicon-organic compounds in the range of 0.01 to 0.2% by weight.
The mold and core optionally have at least one of the following additional features:
The mold and core are manufactured by the method according to any one of claims 1 to 10, and / or the proportion of the mold and core in the range of 0.3 to 2.5% by weight in particular. Containing at least one material from the group consisting of magnesium sulphate, phosphate, and borate, and / or type (d) and core are granular, especially in proportions ranging from 0.1 to 1.0% by weight. Contains silicon dioxide. At least one silicon-organic compound having a polar hydrophilic end and a non-polar hydrophobic end on the surface of a granular mold-based material for use in the method according to any one of claims 1-10. With, mold-based material. Particularly suitable for producing fiber composites or metal or plastic cast parts from granular mold base materials and multi-component binders by 3D printing for use in the method according to any one of claims 1-10. A set for manufacturing plastic molds and cores, wherein the set includes the following:
(A) At least one silicon-organic compound having polar hydrophilic end and non-polar hydrophobic end,
(B) At least one material from the group consisting of water glass, magnesium sulphate, phosphate, and borate, and optionally.
(C) Granular mold base material,
(D) At least one material from the group consisting of silicon dioxide and calcium carbonate, and / or (e) aqueous hydroxide solution.